Portion of an electronic mouse



FIG. 1 is a rear perspective view of the bottom of an electronic mouse showing our new design; and,

FIG. 2 is a bottom view thereof.

The broken line showing of various regions in the Figures, the unshaded areas therein and the remainder of the electronic mouse is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of an electronic mouse, as shown and described. 